/*
 *  Copyright (C) 2009-2010 Howard Chu
 *
 *  This file is part of librtmp.
 *
 *  librtmp is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation; either version 2.1,
 *  or (at your option) any later version.
 *
 *  librtmp is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with librtmp see the file COPYING.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA  02110-1301, USA.
 *  http://www.gnu.org/copyleft/lgpl.html
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>

#include "rtmp_sys.h"
#include "log.h"
#include "http.h"

#ifdef CRYPTO
#ifdef USE_POLARSSL
#include <polarssl/sha2.h>
#ifndef SHA256_DIGEST_LENGTH
#define SHA256_DIGEST_LENGTH	32
#endif
#define HMAC_CTX	sha2_context
#define HMAC_setup(ctx, key, len)	sha2_hmac_starts(&ctx, (unsigned char *)key, len, 0)
#define HMAC_crunch(ctx, buf, len)	sha2_hmac_update(&ctx, buf, len)
#define HMAC_finish(ctx, dig, dlen)	dlen = SHA256_DIGEST_LENGTH; sha2_hmac_finish(&ctx, dig)
#define HMAC_close(ctx)
#elif defined(USE_GNUTLS)
#include <nettle/hmac.h>
#ifndef SHA256_DIGEST_LENGTH
#define SHA256_DIGEST_LENGTH	32
#endif
#undef HMAC_CTX
#define HMAC_CTX	struct hmac_sha256_ctx
#define HMAC_setup(ctx, key, len)	hmac_sha256_set_key(&ctx, len, key)
#define HMAC_crunch(ctx, buf, len)	hmac_sha256_update(&ctx, len, buf)
#define HMAC_finish(ctx, dig, dlen)	dlen = SHA256_DIGEST_LENGTH; hmac_sha256_digest(&ctx, SHA256_DIGEST_LENGTH, dig)
#define HMAC_close(ctx)
#else	/* USE_OPENSSL */
#include <openssl/ssl.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/rc4.h>
#define HMAC_setup(ctx, key, len)	HMAC_CTX_init(&ctx); HMAC_Init_ex(&ctx, (unsigned char *)key, len, EVP_sha256(), 0)
#define HMAC_crunch(ctx, buf, len)	HMAC_Update(&ctx, (unsigned char *)buf, len)
#define HMAC_finish(ctx, dig, dlen)	HMAC_Final(&ctx, (unsigned char *)dig, &dlen);
#define HMAC_close(ctx)	HMAC_CTX_cleanup(&ctx)
#endif

extern void RTMP_TLS_Init();
extern TLS_CTX RTMP_TLS_ctx;

#include <zlib.h>

#endif /* CRYPTO */

#define	AGENT	"Mozilla/5.0"

HTTPResult HTTP_get(struct HTTP_ctx *http, const char *url, HTTP_read_callback *cb)
{
	char *host, *path;
	char *p1, *p2;
	char hbuf[256];
	int port = 80;
#ifdef CRYPTO
	int ssl = 0;
#endif
	int hlen, flen = 0;
	int rc, i;
	int len_known;
	HTTPResult ret = HTTPRES_OK;
	struct sockaddr_in sa;
	RTMPSockBuf sb = {0};

	http->status = -1;

	memset(&sa, 0, sizeof(struct sockaddr_in));
	sa.sin_family = AF_INET;

	/* we only handle http here */
	if (strncasecmp(url, "http", 4))
		return HTTPRES_BAD_REQUEST;

	if (url[4] == 's')
	{
#ifdef CRYPTO
		ssl = 1;
		port = 443;
		if (!RTMP_TLS_ctx)
			RTMP_TLS_Init();
#else
		return HTTPRES_BAD_REQUEST;
#endif
	}

	p1 = strchr(url + 4, ':');
	if (!p1 || strncmp(p1, "://", 3))
		return HTTPRES_BAD_REQUEST;

	host = p1 + 3;
	path = strchr(host, '/');
	hlen = path - host;
	strncpy(hbuf, host, hlen);
	hbuf[hlen] = '\0';
	host = hbuf;
	p1 = strrchr(host, ':');
	if (p1)
	{
		*p1++ = '\0';
		port = atoi(p1);
	}

	sa.sin_addr.s_addr = inet_addr(host);
	if (sa.sin_addr.s_addr == INADDR_NONE)
	{
		struct hostent *hp = gethostbyname(host);
		if (!hp || !hp->h_addr)
			return HTTPRES_LOST_CONNECTION;
		sa.sin_addr = *(struct in_addr *)hp->h_addr;
	}
	sa.sin_port = htons(port);
	sb.sb_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (sb.sb_socket == -1)
		return HTTPRES_LOST_CONNECTION;
	i =
		sprintf(sb.sb_buf,
		"GET %s HTTP/1.0\r\nUser-Agent: %s\r\nHost: %s\r\nReferer: %.*s\r\n",
		path, AGENT, host, (int)(path - url + 1), url);
	if (http->date[0])
		i += sprintf(sb.sb_buf + i, "If-Modified-Since: %s\r\n", http->date);
	i += sprintf(sb.sb_buf + i, "\r\n");

	if (connect
		(sb.sb_socket, (struct sockaddr *)&sa, sizeof(struct sockaddr)) < 0)
	{
		ret = HTTPRES_LOST_CONNECTION;
		goto leave;
	}
#ifdef CRYPTO
	if (ssl)
	{
#ifdef NO_SSL
		RTMP_Log(RTMP_LOGERROR, "%s, No SSL/TLS support", __FUNCTION__);
		ret = HTTPRES_BAD_REQUEST;
		goto leave;
#else
		TLS_client(RTMP_TLS_ctx, sb.sb_ssl);
		TLS_setfd(sb.sb_ssl, sb.sb_socket);
		if (TLS_connect(sb.sb_ssl) < 0)
		{
			RTMP_Log(RTMP_LOGERROR, "%s, TLS_Connect failed", __FUNCTION__);
			ret = HTTPRES_LOST_CONNECTION;
			goto leave;
		}
#endif
	}
#endif
	RTMPSockBuf_Send(&sb, sb.sb_buf, i);

	/* set timeout */
#define HTTP_TIMEOUT	5
	{
		SET_RCVTIMEO(tv, HTTP_TIMEOUT);
		if (setsockopt
			(sb.sb_socket, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof(tv)))
		{
			RTMP_Log(RTMP_LOGERROR, "%s, Setting socket timeout to %ds failed!",
				__FUNCTION__, HTTP_TIMEOUT);
		}
	}

	sb.sb_size = 0;
	sb.sb_timedout = FALSE;
	if (RTMPSockBuf_Fill(&sb) < 1)
	{
		ret = HTTPRES_LOST_CONNECTION;
		goto leave;
	}
	if (strncmp(sb.sb_buf, "HTTP/1", 6))
	{
		ret = HTTPRES_BAD_REQUEST;
		goto leave;
	}

	p1 = strchr(sb.sb_buf, ' ');
	rc = atoi(p1 + 1);
	http->status = rc;

	if (rc >= 300)
	{
		if (rc == 304)
		{
			ret = HTTPRES_OK_NOT_MODIFIED;
			goto leave;
		}
		else if (rc == 404)
			ret = HTTPRES_NOT_FOUND;
		else if (rc >= 500)
			ret = HTTPRES_SERVER_ERROR;
		else if (rc >= 400)
			ret = HTTPRES_BAD_REQUEST;
		else
			ret = HTTPRES_REDIRECTED;
	}

	p1 = memchr(sb.sb_buf, '\n', sb.sb_size);
	if (!p1)
	{
		ret = HTTPRES_BAD_REQUEST;
		goto leave;
	}
	sb.sb_start = p1 + 1;
	sb.sb_size -= sb.sb_start - sb.sb_buf;

	while ((p2 = memchr(sb.sb_start, '\r', sb.sb_size)))
	{
		if (*sb.sb_start == '\r')
		{
			sb.sb_start += 2;
			sb.sb_size -= 2;
			break;
		}
		else
			if (!strncasecmp
				(sb.sb_start, "Content-Length: ", sizeof("Content-Length: ") - 1))
			{
				flen = atoi(sb.sb_start + sizeof("Content-Length: ") - 1);
			}
			else
				if (!strncasecmp
					(sb.sb_start, "Last-Modified: ", sizeof("Last-Modified: ") - 1))
				{
					*p2 = '\0';
					strcpy(http->date, sb.sb_start + sizeof("Last-Modified: ") - 1);
				}
				p2 += 2;
				sb.sb_size -= p2 - sb.sb_start;
				sb.sb_start = p2;
				if (sb.sb_size < 1)
				{
					if (RTMPSockBuf_Fill(&sb) < 1)
					{
						ret = HTTPRES_LOST_CONNECTION;
						goto leave;
					}
				}
	}

	len_known = flen > 0;
	while ((!len_known || flen > 0) &&
		(sb.sb_size > 0 || RTMPSockBuf_Fill(&sb) > 0))
	{
		cb(sb.sb_start, 1, sb.sb_size, http->data);
		if (len_known)
			flen -= sb.sb_size;
		http->size += sb.sb_size;
		sb.sb_size = 0;
	}

	if (flen > 0)
		ret = HTTPRES_LOST_CONNECTION;

leave:
	RTMPSockBuf_Close(&sb);
	return ret;
}

#ifdef CRYPTO

#define CHUNK	16384

struct info
{
	z_stream *zs;
	HMAC_CTX ctx;
	int first;
	int zlib;
	int size;
};

static size_t swfcrunch(void *ptr, size_t size, size_t nmemb, void *stream)
{
	struct info *i = stream;
	char *p = ptr;
	size_t len = size * nmemb;

	if (i->first)
	{
		i->first = 0;
		/* compressed? */
		if (!strncmp(p, "CWS", 3))
		{
			*p = 'F';
			i->zlib = 1;
		}
		HMAC_crunch(i->ctx, (unsigned char *)p, 8);
		p += 8;
		len -= 8;
		i->size = 8;
	}

	if (i->zlib)
	{
		unsigned char out[CHUNK];
		i->zs->next_in = (unsigned char *)p;
		i->zs->avail_in = len;
		do
		{
			i->zs->avail_out = CHUNK;
			i->zs->next_out = out;
			inflate(i->zs, Z_NO_FLUSH);
			len = CHUNK - i->zs->avail_out;
			i->size += len;
			HMAC_crunch(i->ctx, out, len);
		}
		while (i->zs->avail_out == 0);
	}
	else
	{
		i->size += len;
		HMAC_crunch(i->ctx, (unsigned char *)p, len);
	}
	return size * nmemb;
}

static int tzoff;
static int tzchecked;

#define	JAN02_1980	318340800

static const char *monthtab[12] = { "Jan", "Feb", "Mar",
	"Apr", "May", "Jun",
	"Jul", "Aug", "Sep",
	"Oct", "Nov", "Dec"
};
static const char *days[] =
{ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };

/* Parse an HTTP datestamp into Unix time */
static time_t make_unix_time(char *s)
{
	struct tm time;
	int i, ysub = 1900, fmt = 0;
	char *month;
	char *n;
	time_t res;

	if (s[3] != ' ')
	{
		fmt = 1;
		if (s[3] != ',')
			ysub = 0;
	}
	for (n = s; *n; ++n)
		if (*n == '-' || *n == ':')
			*n = ' ';

	time.tm_mon = 0;
	n = strchr(s, ' ');
	if (fmt)
	{
		/* Day, DD-MMM-YYYY HH:MM:SS GMT */
		time.tm_mday = strtol(n + 1, &n, 0);
		month = n + 1;
		n = strchr(month, ' ');
		time.tm_year = strtol(n + 1, &n, 0);
		time.tm_hour = strtol(n + 1, &n, 0);
		time.tm_min = strtol(n + 1, &n, 0);
		time.tm_sec = strtol(n + 1, NULL, 0);
	}
	else
	{
		/* Unix ctime() format. Does not conform to HTTP spec. */
		/* Day MMM DD HH:MM:SS YYYY */
		month = n + 1;
		n = strchr(month, ' ');
		while (isspace(*n))
			n++;
		time.tm_mday = strtol(n, &n, 0);
		time.tm_hour = strtol(n + 1, &n, 0);
		time.tm_min = strtol(n + 1, &n, 0);
		time.tm_sec = strtol(n + 1, &n, 0);
		time.tm_year = strtol(n + 1, NULL, 0);
	}
	if (time.tm_year > 100)
		time.tm_year -= ysub;

	for (i = 0; i < 12; i++)
		if (!strncasecmp(month, monthtab[i], 3))
		{
			time.tm_mon = i;
			break;
		}
		time.tm_isdst = 0;		/* daylight saving is never in effect in GMT */

		/* this is normally the value of extern int timezone, but some
		* braindead C libraries don't provide it.
		*/
		if (!tzchecked)
		{
			struct tm *tc;
			time_t then = JAN02_1980;
			tc = localtime(&then);
			tzoff = (12 - tc->tm_hour) * 3600 + tc->tm_min * 60 + tc->tm_sec;
			tzchecked = 1;
		}
		res = mktime(&time);
		/* Unfortunately, mktime() assumes the input is in local time,
		* not GMT, so we have to correct it here.
		*/
		if (res != -1)
			res += tzoff;
		return res;
}

/* Convert a Unix time to a network time string
* Weekday, DD-MMM-YYYY HH:MM:SS GMT
*/
static void strtime(time_t * t, char *s)
{
	struct tm *tm;

	tm = gmtime((time_t *) t);
	sprintf(s, "%s, %02d %s %d %02d:%02d:%02d GMT",
		days[tm->tm_wday], tm->tm_mday, monthtab[tm->tm_mon],
		tm->tm_year + 1900, tm->tm_hour, tm->tm_min, tm->tm_sec);
}

#define HEX2BIN(a)      (((a)&0x40)?((a)&0xf)+9:((a)&0xf))

int RTMP_HashSWF(const char *url, unsigned int *size, unsigned char *hash,
	int age)
{
	FILE *f = NULL;
	char *path, date[64], cctim[64];
	long pos = 0;
	time_t ctim = -1, cnow;
	int i, got = 0, ret = 0;
	unsigned int hlen;
	struct info in = { 0 };
	struct HTTP_ctx http = { 0 };
	HTTPResult httpres;
	z_stream zs = { 0 };
	AVal home, hpre;

	date[0] = '\0';
#ifdef _WIN32
#ifdef XBMC4XBOX
	hpre.av_val = "Q:";
	hpre.av_len = 2;
	home.av_val = "\\UserData";
#else
	hpre.av_val = getenv("HOMEDRIVE");
	hpre.av_len = strlen(hpre.av_val);
	home.av_val = getenv("HOMEPATH");
#endif
#define DIRSEP	"\\"

#else /* !_WIN32 */
	hpre.av_val = "";
	hpre.av_len = 0;
	home.av_val = getenv("HOME");
#define DIRSEP	"/"
#endif
	if (!home.av_val)
		home.av_val = ".";
	home.av_len = strlen(home.av_val);

	/* SWF hash info is cached in a fixed-format file.
	* url: <url of SWF file>
	* ctim: HTTP datestamp of when we last checked it.
	* date: HTTP datestamp of the SWF's last modification.
	* size: SWF size in hex
	* hash: SWF hash in hex
	*
	* These fields must be present in this order. All fields
	* besides URL are fixed size.
	*/
	path = malloc(hpre.av_len + home.av_len + sizeof(DIRSEP ".swfinfo"));
	sprintf(path, "%s%s" DIRSEP ".swfinfo", hpre.av_val, home.av_val);

	f = fopen(path, "r+");
	while (f)
	{
		char buf[4096], *file, *p;

		file = strchr(url, '/');
		if (!file)
			break;
		file += 2;
		file = strchr(file, '/');
		if (!file)
			break;
		file++;
		hlen = file - url;
		p = strrchr(file, '/');
		if (p)
			file = p;
		else
			file--;

		while (fgets(buf, sizeof(buf), f))
		{
			char *r1;

			got = 0;

			if (strncmp(buf, "url: ", 5))
				continue;
			if (strncmp(buf + 5, url, hlen))
				continue;
			r1 = strrchr(buf, '/');
			i = strlen(r1);
			r1[--i] = '\0';
			if (strncmp(r1, file, i))
				continue;
			pos = ftell(f);
			while (got < 4 && fgets(buf, sizeof(buf), f))
			{
				if (!strncmp(buf, "size: ", 6))
				{
					*size = strtol(buf + 6, NULL, 16);
					got++;
				}
				else if (!strncmp(buf, "hash: ", 6))
				{
					unsigned char *ptr = hash, *in = (unsigned char *)buf + 6;
					int l = strlen((char *)in) - 1;
					for (i = 0; i < l; i += 2)
						*ptr++ = (HEX2BIN(in[i]) << 4) | HEX2BIN(in[i + 1]);
					got++;
				}
				else if (!strncmp(buf, "date: ", 6))
				{
					buf[strlen(buf) - 1] = '\0';
					strncpy(date, buf + 6, sizeof(date));
					got++;
				}
				else if (!strncmp(buf, "ctim: ", 6))
				{
					buf[strlen(buf) - 1] = '\0';
					ctim = make_unix_time(buf + 6);
					got++;
				}
				else if (!strncmp(buf, "url: ", 5))
					break;
			}
			break;
		}
		break;
	}

	cnow = time(NULL);
	/* If we got a cache time, see if it's young enough to use directly */
	if (age && ctim > 0)
	{
		ctim = cnow - ctim;
		ctim /= 3600 * 24;	/* seconds to days */
		if (ctim < age)		/* ok, it's new enough */
			goto out;
	}

	in.first = 1;
	HMAC_setup(in.ctx, "Genuine Adobe Flash Player 001", 30);
	inflateInit(&zs);
	in.zs = &zs;

	http.date = date;
	http.data = &in;

	httpres = HTTP_get(&http, url, swfcrunch);

	inflateEnd(&zs);

	if (httpres != HTTPRES_OK && httpres != HTTPRES_OK_NOT_MODIFIED)
	{
		ret = -1;
		if (httpres == HTTPRES_LOST_CONNECTION)
			RTMP_Log(RTMP_LOGERROR, "%s: connection lost while downloading swfurl %s",
			__FUNCTION__, url);
		else if (httpres == HTTPRES_NOT_FOUND)
			RTMP_Log(RTMP_LOGERROR, "%s: swfurl %s not found", __FUNCTION__, url);
		else
			RTMP_Log(RTMP_LOGERROR, "%s: couldn't contact swfurl %s (HTTP error %d)",
			__FUNCTION__, url, http.status);
	}
	else
	{
		if (got && pos)
			fseek(f, pos, SEEK_SET);
		else
		{
			char *q;
			if (!f)
				f = fopen(path, "w");
			if (!f)
			{
				int err = errno;
				RTMP_Log(RTMP_LOGERROR,
					"%s: couldn't open %s for writing, errno %d (%s)",
					__FUNCTION__, path, err, strerror(err));
				ret = -1;
				goto out;
			}
			fseek(f, 0, SEEK_END);
			q = strchr(url, '?');
			if (q)
				i = q - url;
			else
				i = strlen(url);

			fprintf(f, "url: %.*s\n", i, url);
		}
		strtime(&cnow, cctim);
		fprintf(f, "ctim: %s\n", cctim);

		if (!in.first)
		{
			HMAC_finish(in.ctx, hash, hlen);
			*size = in.size;

			fprintf(f, "date: %s\n", date);
			fprintf(f, "size: %08x\n", in.size);
			fprintf(f, "hash: ");
			for (i = 0; i < SHA256_DIGEST_LENGTH; i++)
				fprintf(f, "%02x", hash[i]);
			fprintf(f, "\n");
		}
	}
	HMAC_close(in.ctx);
out:
	free(path);
	if (f)
		fclose(f);
	return ret;
}
#else
int RTMP_HashSWF(const char *url, unsigned int *size, unsigned char *hash,
	int age)
{
	return -1;
}
#endif
